The present invention relates to a structure inspection method for a structured document.
In a computer system where a process request is received via a communication network to perform a requested application process, the data structure of an electronic document describing the request is generally checked for consistency with a predetermined structure each time it is received. The computer used in the system performs the requested application process and returns the result only when the document structure is consistent with the predetermined structure. If, on the other hand, the document structure is inconsistent with the predetermined structure, the computer returns an error to the requesting source.
The above document structure inspection process can be performed simultaneously with an application process. However, if any document structure inconsistency is found at a final stage of the application process, all the previously performed application process steps are wasted so that the processing efficiency decreases. To prevent the processing efficiency from decreasing, it is preferred that the entire document structure be inspected before the application process. This also holds true when the received electronic document is expressed in XML (Extensible Markup Language).
The interface of an inspection process for checking whether the structures of various structured documents are consistent with a predefined document structure is stipulated as described under “Schema Validation” in “Java API for XML Processing Version 1.2 Final Release” (Reference Document 1), which is written by Rajiv Mordani et al. with reference to Java (registered trademark of Sun Microsystems). Further, “Xerces 2 Java Parser Readme” (Reference Document 2) of the Apache Software Foundation describes how to implement a structure inspection process for such structured documents.
In a computer system for transmitting/receiving electronic documents via a communication network, the electronic documents to be transmitted may be electronically signed by a sender or encrypted for the purpose of preventing the transmitted documents from being falsified or viewed by an unauthorized person.
In a computer system comprising a plurality of computers, which sequentially perform various processes to carry out a complicated process as a whole, a process requesting person, who is the initial sender, may electronically sign or encrypt part of the data to be transmitted.
The above processing operation is performed, for instance, for on-line shopping. When a payment is made with a credit card for on-line shopping purposes, the data to be transmitted from the purchaser (initial sender) to an on-line shopping site manager includes the information identifying the item to be purchased and the information identifying the credit card (card number, expiration date, etc.) used for payment. The information about the credit card is forwarded from the on-line shopping site manager to a credit card company where a credit-card settlement process is performed. The on-line shopping site manager does not directly use the credit card information, but receive it from the purchaser and relay it to the credit card company.
In the system described above, a higher degree of safety is achieved by the use of a transmission method in which the purchaser encrypts part of the credit card information so as to permit only the credit card company to decrypt it while keeping it from being disclosed to the on-line shopping site manager than the use of a transmission method in which the data to be transmitted is entirely encrypted by the on-line shopping site manager. In this instance, the encrypted data may be electronically signed (partial signature) to indicate that the credit card information is encrypted by the purchaser. It is anticipated that the above electronic transactions will prevail in the future due to widespread use of a public key cryptography technology.
There is a technology that converts a document structure definition written in a certain document structure definition language into an equivalent document structure definition written in another language. For example, a conversion tool named “dtd2xs” is introduced in “LuMrix, ‘XML Tools’, ‘online’, 2003, [retrieved on Feb. 14, 2003], Internet <URL: http://puvogel.informatik.med.uni-giessen.de/lumrix/#dtd>” (Reference Document 3). This tool converts a document structure definition written in document definition language DTD into an equivalent document structure definition written in “W3C XML Schema”. When used to effect conversion among various document structure definition languages, however, the tool does not yield a perfectly equivalent document structure definition due, for instance, to different description capabilities of the document structure definition languages.